CN102181285A - Silica nitride fluorescent powder and preparation method thereof - Google Patents

Abstract

The invention provides a silicon oxynitride fluorescent powder, the general formula is: Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d , wherein -2<a<2,-2<b<2,-2<c<2,-2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D =2, e>0 , v _C , v _D represent C, the valence state of D; C is selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, The luminescent center of one or several elements in Fe, D is a mixture of alkaline earth metals other than Ba and one or several elements in Zn. When the silicon oxynitride phosphor is exposed to the excitation source for a long time, the brightness decreases little, the conversion efficiency to blue light or near ultraviolet light is excellent, the color purity is excellent, the thermal stability and chemical stability are high, and the grain size is small and uniform; sintering The temperature is low, the process is simple, the industrial continuous production is easy, and the invention has broad industrial application prospects.

Description

A kind of silicon oxynitride fluorescent powder and preparation method thereof

technical field

The invention relates to the field of inorganic luminescent materials, in particular to a silicon oxynitride fluorescent powder and a preparation method thereof.

Background technique

Compared with traditional lighting technology, White Light Emitting Diodes (WLED) lighting technology has its significant advantages: light-emitting diodes have small size, low calorific value, low power consumption, long life, fast response, environmental protection, etc. Advantages, flat packaging and easy thinning and other advantages. Among them, white LEDs excited by near-ultraviolet and blue light (360nm-450nm) are widely used in automotive lighting, backlight and other electronic devices. The new Plasma Display Panel (PDP) has the advantages of small size, lighter weight, no X-ray radiation, high brightness, good color reproduction, rich grayscale, and fast response to rapidly changing pictures. More lighting display technologies include trichromatic fluorescent lamps, fluorescent display tubes (VFD), field emission displays (FED), cathode ray tubes (CRT) and so on.

The performance of the above illuminated display devices depends on many factors, among which the phosphor powder used for light conversion also plays an important role. For any of these uses, in order to make the phosphor emit light, it is necessary to provide the phosphor with energy that excites the phosphor, including electron rays, vacuum ultraviolet rays, ultraviolet rays, and even visible light. Under the excitation of the excitation source that provides these energies, the phosphor powder emit visible light.

There are many types of phosphors, including silicate phosphors, phosphate phosphors, aluminate phosphors, sulfide phosphors, etc. Phosphors have the problem of brightness reduction when exposed to excitation sources for a long time. Therefore, it is necessary to explore new phosphor materials with small brightness reduction and stable performance.

Contents of the invention

The problem to be solved by the present invention is to provide a silicon oxynitride fluorescent powder with high thermal and chemical stability and high light conversion efficiency.

In order to solve the problems of the technologies described above, the technical solution of the present invention is:

A silicon oxynitride phosphor, the general formula is: Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d , where -2<a<2, -2<b<2, -2<c<2, -2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D =2, e>0, v _C , v _D represents C, the valence state of D; C is one selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, Fe The luminescent center of one or several elements, D is the mixture of alkaline earth metals other than Ba and one or several elements in Zn.

Preferably, the general formula of the silicon oxynitride phosphor is: Ba _1-fg C _f D _g Si ₃ (Al, Ga, In) ₃ O ₄ N ₅ , 0≤f≤0.30, 0≤g≤0.5 C is the luminescence center of one or more elements selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, Fe, D is an alkaline earth metal other than Ba and a mixture of one or more elements among metal elements.

Preferably, its basic structure is a monoclinic crystal structure composed of BaSi ₃ Al ₃ O ₄ N ₅ , and its crystal phase has diffraction peaks at the following three 2θ in the XRD diffraction test using CuKα as the X-ray source: 24.3° -26.3°, 30.7°-32.7°, 35.6°-37.6°.

Preferably, said Si may be partially substituted by Ge or B.

Preferably, the C is a luminescence center containing at least one element among Ce, Sm, Eu or Yb.

Preferably, the maximum emission wavelength in the fluorescence spectrum is 460nm-500nm, the maximum excitation wavelength in the excitation spectrum is 240nm-420nm, and the maximum excitation wavelength in the vacuum ultraviolet excitation is 140nm-155nm.

Preferably, the maximum emission wavelength in the fluorescence spectrum is 400nm-440nm, and the maximum excitation wavelength in the excitation spectrum is 250nm-370nm.

Preferably, the maximum emission wavelength in the fluorescence spectrum is 300nm-550nm, and the maximum excitation wavelength in the excitation spectrum is 650nm-740nm.

A preparation method of silicon oxynitride fluorescent powder, comprising the following steps:

1) According to the chemical expression Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d , calculate the amount of each raw material according to the ratio of each element, where -2<a <2, -2<b<2, -2<c<2, -2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D =2, e>0, v _C , v _D represents C, the valence state of D; C is selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, Fe The luminescent center of one or more elements in D, D is a mixture of alkaline earth metals other than Ba and one or more elements in Zn;

Each raw material is: one or several barium-containing compounds in barium oxide or barium carbonate or barium oxalate that can be converted into barium oxide, including Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, One or several elements of Tm, Yb, Mn, Cr, Bi, Pb, Fe, oxides, nitrides or compounds that can be converted into oxides or nitrides, containing alkaline earth metals other than Ba and one of Zn Or several simple substances, oxides, nitrides or compounds that can be converted into oxides or nitrides, Si-containing oxides, nitrides or compounds that can be converted into oxides or nitrides;

2) Mix the above-mentioned various raw materials, and heat the mixture to 1400°C-1600°C in a reducing atmosphere for roasting, keep it warm for 2h-40h, and naturally cool to room temperature;

3) Pulverize the powder obtained after firing to a particle size of 10 μm or less.

Preferably, the raw materials in 2) further include oxides, nitrides or compounds that can be converted into oxides or nitrides containing Ge or B.

As a preference, after mixing the above-mentioned various raw materials in the above 2), a co-solvent H ₃ BO ₃ or BaF ₂ is also added.

As a preference, the mixing device used for mixing the above-mentioned various raw materials in 2) is a V-shaped mixer, a shaking mixer, a ball mill, or a vibrating ball mill.

Preferably, after mixing the above various raw materials in 2), the mixture is placed in a crucible with low reactivity with boron nitride, silicon nitride, tungsten, molybdenum or aluminum oxide.

As a preference, after the above-mentioned various raw materials are mixed in the above 2), the bulk relative density is controlled at 20%-40%.

Preferably, the reducing atmosphere in 2) is one or more mixed atmospheres of nitrogen, hydrogen or ammonia.

Preferably, the pressure of the reducing atmosphere is above 1 atm.

Preferably, the heating rate of the mixture in the above 2) is 1°C/min-10°C/min.

Preferably, the furnace used in the 2) calcination is a metal resistance heating type, a graphite resistance heating type or a silicon molybdenum rod resistance heating type continuous furnace or batch furnace.

A fluorescent powder composition, comprising the aforementioned silicon oxynitride fluorescent powder, the silicon oxynitride fluorescent powder accounting for more than 25% by weight of the fluorescent powder composition.

An illuminating device includes a luminescent light source and the silicon oxynitride fluorescent powder, and the illuminating device is a white LED lamp or a trichromatic fluorescent lamp.

Preferably, the luminous light source is an LED with a luminous wavelength of 320nm-470nm.

An image display device, comprising an excitation source and the silicon oxynitride phosphor powder, the image display device is one of a fluorescent display tube, a field emission display, a plasma display, a cathode ray tube, and a high-resolution television .

Preferably, the excitation source is one of electron rays, electric field, vacuum ultraviolet rays or ultraviolet rays.

A silicon oxynitride fluorescent powder provided by the present invention adopts a new silicon nitride oxide as a matrix material, and when exposed to an excitation source for a long time, the brightness decreases little, and the conversion efficiency to blue light or near-ultraviolet light is excellent and the color purity is excellent. High thermal stability and chemical stability, can resist high temperature and acid environment erosion, small and uniform grain size, is a high-performance phosphor; and compared with the general silicon-based oxynitride, the sintering temperature is lower, the process is simple, It is easy for industrialized continuous production and has broad industrial application prospects. By using the silicon oxynitride phosphor and the phosphor composition containing the silicon oxynitride phosphor, high-efficiency and high-characteristic light-emitting devices, such as lighting devices and image display devices, can be obtained.

Description of drawings

Fig. 1 is the XRD spectrogram of the obtained powder of embodiment 1 of the present invention;

Fig. 2 is the excitation and emission spectrogram of the powder obtained in Example 1 of the present invention;

Fig. 3 is the excitation and emission spectrogram of the powder obtained in Example 2 of the present invention;

Fig. 4 is the excitation and emission spectrogram of powder obtained in Example 3 of the present invention;

Fig. 5 is the excitation and emission spectrogram of powder obtained in Example 4 of the present invention;

Fig. 6 is the excitation and emission spectrogram of the powder obtained in Example 5 of the present invention;

Fig. 7 is the excitation and emission spectrogram of the powder obtained in Example 6 of the present invention;

Fig. 8 is the excitation and emission spectrogram of the powder obtained in Example 7 of the present invention;

Fig. 9 is the excitation and emission spectrogram of the powder obtained in Example 8 of the present invention;

Figure 10 is the excitation and emission spectrograms of the powder obtained in Example 9 of the present invention;

Fig. 11 is the excitation and emission spectrograms of the powder obtained in Example 10 of the present invention;

Fig. 12 is the excitation and emission spectrograms of the powder obtained in Example 11 of the present invention;

Fig. 13 is the excitation and emission spectrogram of the powder obtained in Example 12 of the present invention;

Fig. 14 is the excitation and emission spectra of the powder obtained in Example 13 of the present invention.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only to further illustrate the features and advantages of the present invention, rather than limiting the claims of the present invention.

The present inventors have carried out long-term, in-depth and systematic research on the luminescence characteristics of rare earth-doped barium-containing silicon-aluminum oxynitrides and rare earth ions, combined with the previous α-sialon and β-sialon ceramic powders, and found a A brand-new phosphor with good luminous efficiency unknown so far, its general formula is: Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d , where -2<a<2, -2<b<2, -2<c<2, -2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D =2, e>0, v _C , v _D represent the valence state of C and D; C is selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi , Pb, the luminescent center of one or more elements in Fe, D is a mixture of alkaline earth metals other than Ba and one or more elements in Zn.

The preferred general formula is: Ba _1-fg C _f D _g Si ₃ (Al, Ga, In) ₃ O ₄ N ₅ , and the elements and subscripts represented by each letter are the same as above.

The basic structure of the phosphor powder with the general formula Ba _1-fg C _f D _g Si ₃ (Al, Ga, In) ₃ O ₄ N ₅ is a monoclinic crystal structure composed of BaE ₃ Al ₃ O ₄ N ₅ . Doped with a certain amount of Eu ²⁺ and other luminescent ions, it can be excited by electron rays (for FED, CRT), vacuum ultraviolet (for PDP), ultraviolet (for three-color fluorescent lamps), and near ultraviolet and blue light (for LEDs). Compared with ordinary phosphors, the new high-efficiency phosphors show high luminous efficiency, and the light decay is relatively small under the excitation source for a long time. Al-O, Si-N, Al-N, and Si-O tetrahedra are combined into a three-dimensional framework structure through a certain space, and Ba atoms are distributed in these three-dimensional framework structures. Among them, Al can be partially replaced by other trivalent elements, and Ba can also be partially replaced by other metal ions. At the same time, some Si-O bonds and Al-N bonds can be replaced to a certain extent. The formula is as shown above: Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d . The crystal phase of the base material with this basic structure has diffraction peaks at the following three 2θ in the XRD diffraction test using CuKα as the X-ray source: 24.3°-26.3°, 30.7°-32.7°, 35.6°-37.6°.

The doping position of luminescent ions (such as Eu ²⁺ ) generally replaces the position of Ba ²⁺ , the doping amount is relative to Ba ²⁺ , the mole fraction can vary between 0% and 30%, and the doping range with high brightness is preferred Between 1% and 20%, the selected luminescent ions can be rare earth ions, Mn ²⁺ , Cr ³⁺ , Bi ^{3+ ,} etc., or a combination of the above luminescent ions. The phosphor powder of the present invention has different excitation spectra and emission spectra depending on the composition of the phosphor powder, and can be arbitrarily set as a phosphor powder with various luminescence spectra by properly combining and selecting it. .

Where Si can be partially replaced by Ge or B, the preferred crystal phase is formed by solid solution of BaSi ₃ Al ₃ O ₄ N ₅ single phase, but it can also be mixed with other crystal phases or amorphous phases within the range of not reducing performance And constitute.

C is preferably the luminescence center of one or several elements containing at least Ce, or it can be the luminescence center of one or several elements containing at least Sm, or it can be the luminescence center of one or several elements containing at least Eu , can also be a luminescent center containing at least one or several elements of Yb.

Since there are many different cases of C doping, the prepared phosphors have different wavelength ranges in the fluorescence spectrum, excitation spectrum and vacuum ultraviolet excitation. In the fluorescence spectrum, the maximum luminous wavelength is 460nm-500nm. The maximum excitation wavelength is 240nm-420nm, and the maximum excitation wavelength is 140nm-155nm in vacuum ultraviolet excitation; or the maximum emission wavelength is 400nm-440nm in the fluorescence spectrum, and the maximum excitation wavelength is 250nm-370nm in the excitation spectrum; or in the fluorescence spectrum The maximum luminescent wavelength in the medium is 300nm-550nm, and the maximum excitation wavelength in the excitation spectrum is 650nm-740nm.

For single-doped Eu ²⁺ phosphors, blue phosphors with a maximum emission wavelength of 450nm-500nm can be obtained, and its excitation spectrum can be a wide range of vacuum ultraviolet band 140nm-160nm and ultraviolet-visible light band 220nm-420nm.

The present invention also provides a preparation method of fluorescent powder, comprising the following steps:

1) According to the chemical expression Ba _e C _f D _g E _3+a (Al, Ga, In) _3+b O _4+c N _5+d , calculate the amount of each raw material according to the ratio of each element, where -2<a <2, -2<b<2, -2<c<2, -2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D =2, e>0, v _C , v _D represents C, the valence state of D; C is selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, Fe D is the luminescent center of one or more elements in D, and D is a mixture of alkaline earth metals other than Ba and one or more elements in Zn.

Each raw material is: one or several barium-containing compounds in barium oxide or barium carbonate or barium oxalate that can be converted into barium oxide, including Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, One or several elements of Tm, Yb, Mn, Cr, Bi, Pb, Fe, oxides, nitrides or compounds that can be converted into oxides or nitrides, containing alkaline earth metals other than Ba and one of Zn Or several simple substances, oxides, nitrides or compounds that can be converted into oxides or nitrides, Si-containing oxides, nitrides or compounds that can be converted into oxides or nitrides, such as silicon nitride, dioxide For silicon or pure silicon powder, you can also choose Ge or B-containing oxides, nitrides or compounds that can be converted into oxides or nitrides, so that part of Si is replaced by Ge or B.

In order to fully disperse and contact various raw materials during the reaction process, and finally make the reactants fully react and crystallize at high temperature, it is preferable to add co-solvent H ₃ BO ₃ or BaF ₂ after mixing the above-mentioned various raw materials.

2) The above-mentioned various raw materials can be mixed by dry mixing or wet mixing in an inert solvent that does not substantially react with the ingredients of the raw materials and then removing the solvent.

The mixing device used for mixing can use a V-type mixer, a shaking mixer, a ball mill, a vibrating ball mill, and after mixing, the mixture can be stored in a low reactive inside the crucible. The bulk relative density is controlled at 20%-40%. If the bulk density is too small, the solid-phase diffusion distance will be long due to the small contact area between the raw material powders, or there is no suitable diffusion path, so that the solid-phase reaction is difficult to complete, and a large number of impurities that contribute little to the luminescent performance may remain On the other hand, when the bulk density is too large, the resulting phosphors tend to form hard agglomerates, which not only require a long pulverization step, but also tend to reduce the luminous efficiency of the phosphors and increase the possibility of introducing impurities.

After mixing, the mixture is heated to 1400°C-1600°C in reducing atmosphere for calcination, kept for 2h-40h, and naturally cooled to room temperature.

The reducing atmosphere is one or more mixed atmospheres of nitrogen, hydrogen or ammonia, preferably containing nitrogen, and the pressure of the reducing atmosphere is above 1 atm.

Preferably, the mixture is heated and roasted at a rate of 1°C/min-10°C/min, and a continuous or batch furnace of metal resistance heating type, graphite resistance heating type or silicon molybdenum rod resistance heating type can be used, and the mixture is preferably heated to 1450 ℃～1600℃ for firing. If the sintering temperature is too low, it is difficult to carry out the solid-state reaction and cannot synthesize the required phosphor, even the synthesized phosphor has poor crystallization properties, thereby affecting the luminous intensity; while the sintering temperature is too high, the obtained phosphor is easy to form Hard aggregates may even volatilize and decompose, which will also affect the luminescent performance. A reasonable sintering temperature can inhibit the formation of hard aggregates under the premise of fully developed grains.

3) Pulverize the powder obtained after firing to a particle size of 10 μm or less. It can be pulverized by a pulverizer commonly used in the industry, such as a ball mill, etc., preferably pulverized to 0.1-5 μm, because when the particle size is too large, the fluidity and dispersibility of the powder will deteriorate and the luminous intensity will be uneven when forming a light-emitting device. When the particle size becomes 0.1 μm or less, the proportion of defects on the surface increases, resulting in a decrease in luminous intensity.

The present invention also provides a phosphor composition, including the silicon oxynitride phosphor powder provided by the present invention, wherein the silicon oxynitride phosphor accounts for more than 25% by weight of the phosphor composition.

The present invention also provides an illuminating device, which includes a luminescent light source and silicon oxynitride fluorescent powder, and the illuminating device is a white LED lamp or a trichromatic fluorescent lamp. The luminous light source is an LED with a luminous wavelength of 320nm-470nm.

The lighting device can be prepared by using the luminescent light source and the phosphor composition provided by the present invention. In addition to selecting the phosphor composition of the present invention alone, it can also be used in combination with phosphors with other luminescent properties to form a lighting device of desired color. For example, a 330-420nm ultraviolet LED light-emitting device and a green phosphor that emits a 520-570nm wavelength after being excited by this wavelength, a red phosphor that emits a 570-700nm light, and the BaAl ₃ Si doped with Eu ²⁺ of the present invention Combination of ₃ O ₄ N ₅ to obtain white LED with high color rendering index, green phosphor, BaMgAl ₁₀ O ₁₇ doped with Eu or Mn, or SrSi ₂ N ₂ O ₂ doped with Eu, red phosphor , Eu-doped Y ₂ O ₃ or Eu-doped CaAlSiN ₃ can be used.

The present invention also provides a kind of image display device, comprises excitation source and silicon oxynitride fluorescent powder, uses the fluorescent powder composition provided by the present invention to get final product, and image display device is fluorescent display tube (VFD), field emission display (FED) ), plasma display (PDP), cathode ray tube (CRT), and high-definition television (HDTV). The excitation source is one of electron ray, electric field, vacuum ultraviolet ray or ultraviolet ray. For example, vacuum ultraviolet rays of 100-190 nm, ultraviolet-visible light of 220-420 nm, and electron rays can be used to excite the phosphor composition of the present invention.

The specific preparation process of the silicon oxynitride fluorescent powder provided by the present invention is as follows. The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, reducing gases, etc. Instructions are available commercially.

Example 1

According to the chemical formula Ba _0.85 Eu _0.15 Si ₃ Al ₃ O ₄ N ₅ , weigh 2.6560g BaCO ₃ , 1.7536g Si ₃ N ₄ , 0.3168g Eu ₂ O ₃ , 0.4968g AlN, 1.2186g Al ₂ O ₃ starting powder, and add 0.1288gH ₃ BO ₃ is used as a flux, and they are put into a silica mortar and ground for 20 minutes to fully mix various raw materials. Put the mixed powder into a BN crucible with a bulk relative density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, and vacuumize the high-temperature furnace to reduce the oxygen content , and then feed the mixed reducing gas, that is, in the ambient atmosphere of flowing N ₂ /NH ₃ (the volume ratio of which is 10:1) with a purity of 99.999%, the temperature is raised to 800° C. at a heating rate of 10° C./min, and then the temperature is raised to 800° C. at a rate of 5 Raise the temperature to 1550°C at a heating rate of ℃/min, keep it warm for 4 hours, then cool down to 800°C at a cooling rate of 10°C/min, then cool naturally to room temperature, take out the obtained powder and grind it into a powder in a mortar. Get the desired phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation emission spectrum and comparing with commercial BAM blue powder. Fig. 1 shows the XRD spectrum of the obtained phosphor, which is a single phase at 24.3-26.3°, 30.7-32.7°, 35.6-37.6°. With three strong peaks, the positions and intensities of the diffraction peaks will shift to a certain extent for different doping of luminescent ions, as well as solid solution of other ions. Figure 2 shows (the small picture is the fluorescence spectrum of the sample under vacuum ultraviolet), the obtained phosphor can be excited by a wide band from vacuum ultraviolet and near ultraviolet to blue light, and emits bright blue light with a center wavelength of 474nm. The excitation and emission intensity is 20% higher than commercial BAM blue powder.

Example 2

According to the chemical formula Ba _0.95 Ce _0.05 Si ₃ Al ₃ O ₄ N ₅ , weigh 2.2345g Ba(NO ₃ ) ₂ , 0.9139g Al ₂ O ₃ , 0.3726g AlN, 1.3151g _{Si 3} N ₄ , 0.0775g CeO ₂ starting powder, put together Put it into a silicon nitride mortar and grind it for 20 minutes to fully mix various raw materials. Put the mixed powder into the BN crucible, the bulk relative density is about 30%, then cover the non-sealed top cover, put the BN crucible into the graphite crucible, and finally put the graphite crucible into the vacuum carbon tube furnace, first Carry out vacuuming operation, then feed flowing _N2 gas with a purity of 99.999%, raise the temperature to 800°C at a heating rate of 4°C/min, and then raise the temperature to 1200°C at a heating rate of 6°C/min, and finally 5°C/min The heating rate of min was raised to 1600°C for 8 hours, and then the temperature was lowered to 1200°C at a cooling rate of 5°C/min, and then naturally cooled to room temperature. The obtained powder was taken out and ground into a powder in a mortar to obtain the desired of fluorescent powder. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra. As shown in Figure 3, the obtained phosphor can be excited by a wide band from near-ultraviolet to blue light, and emit bright blue light with a central emission wavelength of 437nm. Different blue light emission can be achieved by Eu and Ce elements, which play an important role in the color purity of the conditional blue light.

Example 3

According to the chemical formula Ba _0.94 Sm _0.06 Si ₃ Al ₃ O ₄ N ₅ , weigh 2.2109g Ba(NO ₃ ) ₂ , 0.9139g Al ₂ O ₃ , 0.3726g AlN, 1.3151g Si ₃ N ₄ , 0.0942gSm ₂ O ₃ , and add 0.0244 gNH ₄ Cl as a co-solvent, put them into a silicon nitride mortar and grind for 20 minutes to fully mix various raw materials. Put the mixed powder into a BN crucible with a bulk relative density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, and vacuumize the high-temperature furnace to reduce the oxygen content , and then feed mixed reducing gas, that is, in the ambient atmosphere of flowing N ₂ /H ₂ (its volume ratio is 95:5) with a purity of 99.999%, the temperature is raised to 1000° C. at a heating rate of 10° C./min, and then the temperature is raised to 4 Raise the temperature to 1550°C at a heating rate of ℃/min, keep it warm for 6 hours, then cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder and grind it into a powder in a mortar. Get the desired phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectrum, as shown in Figure 4, the obtained phosphor can be excited by a strong broadband from near ultraviolet to blue light to green light, and emit bright red light. The wavelength is 699nm. It is particularly worth noting that the powder has a strong excitation in the blue light band, and can be used as a red phosphor for GaN LEDs to improve the color purity of white light.

Example 4

According to the chemical formula Ba _0.95 Yb _0.05 Si ₃ Al ₃ O ₄ N ₅ , weigh 2.2580g Ba(NO ₃ ) ₂ , 0.9139g Al ₂ O ₃ , 0.3726g AlN, 1.3151g Si ₃ N ₄ , 0.0709gYb ₂ O ₃ , and use 5at% Fractions of BaF ₂ as Ba source instead of Ba(NO ₃ ) ₂ as co-solvent were put together into a silicon nitride mortar and ground for 20 minutes to fully mix various raw materials. Put the mixed powder into a BN crucible with a bulk relative density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, and vacuumize the high-temperature furnace to reduce the oxygen content , and then feed the mixed reducing gas, that is, in the ambient atmosphere of flowing N ₂ /NH ₃ (its volume ratio is 20:1) with a purity of 99.999%, the temperature is raised to 1000° C. at a heating rate of 5° C./min, and then the temperature is raised to 4 Raise the temperature to 1550°C at a heating rate of ℃/min, keep it warm for 4 hours, then cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder and grind it into a powder in a mortar. Get the desired phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectrum, as shown in Figure 5, the obtained phosphor can be excited by a wide band from near ultraviolet to blue light, and emit bright green light with a center wavelength of 535nm. The excitation of the sample in the blue light band is particularly attractive. In view of the excellent thermal stability of the sample, it can be used as a green phosphor for white LEDs.

Example 5

According to the chemical formula Ba _0.98 Mn _0.02 Si ₃ Al ₃ O ₄ N ₅ , weigh 1.7405g BaCO ₃ , 0.0207g MnCO ₃ , 0.9139g _{Al 2} O ₃ , 1.3151g _{Si 3} N ₄ , 0.3726g AlN starting powder, and put them into the agate mortar together Fully grind in medium for 20 minutes, so that all kinds of raw materials are fully mixed. Put the mixed powder into the BN crucible, the bulk relative density is about 30%, then cover the non-sealed top cover, put it into the corundum tube furnace, vacuumize the high temperature furnace, and then pass the mixed reducing gas That is, in the ambient atmosphere of flowing N ₂ /NH ₃ (the volume ratio is 4:1) with a purity of 99.999%, the temperature is raised to 1000°C at a heating rate of 5°C/min, and then the temperature is raised at a heating rate of 4°C/min Keep the temperature at 1600°C for 6 hours, then cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the required phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra, as shown in Figure 6, the obtained phosphor can be excited by a wide band from near ultraviolet to blue light, and emit bright blue light at 370nm and 440nm.

Example 6

According to the chemical formula Ba _0.8 Eu _0.15 Sm _0.05 Si ₃ Al ₃ O ₄ N ₅ , weigh 2.5089gBa(NO ₃ ) ₂ , 0.3168g Eu ₂ O ₃ , 0.0942gSm ₂ O ₃ , 1.2186gAl ₂ O ₃ , 1.7536gSi ₃ N ₄ , 0.4968g AlN, and BaF ₂ was added as a cosolvent as the starting powder according to Ba accounting for 2at% of the total Ba source, and they were put into an agate mortar and ground for 20 minutes to fully mix various raw materials. Put the mixed powder into the BN crucible, the bulk relative density is about 30%, then cover the non-sealed top cover, put it into the corundum tube furnace, vacuumize the high temperature furnace, and then pass the mixed reducing gas That is, in the ambient atmosphere of flowing N ₂ /NH ₃ (the volume ratio is 5:1) with a purity of 99.999%, the temperature is raised to 1000°C at a heating rate of 5°C/min, and then the temperature is raised at a heating rate of 4°C/min Keep the temperature at 1550°C for 6 hours, then cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the required phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra, as shown in Figure 7, the obtained phosphor can be excited by a wide band from near ultraviolet to blue light, and emit bright blue light and red light, with center wavelengths of 467nm and 699nm respectively. Under the excitation of the same near-ultraviolet or blue light, the obtained phosphor will have blue and red emission peaks at the same time, and the green phosphor with similar excitation spectrum (such as BaSi ₃ Al ₃ O ₄ N ₅ :Yb ^{2 +} green phosphor) for white light.

Example 7

According to the chemical formula Ba _0.55 Sr _0.4 Eu _0.15 Si ₃ Al ₃ O ₄ N ₅ , weigh 0.3168g Eu ₂ O ₃ , 1.2186g Al ₂ O ₃ , 1.7536g Si ₃ N ₄ , 0.4968g AlN, 1.0656g BaCO ₃ and 0.7086g SrCO ₃ as The starting powder is put into a silicon nitride mortar and ground for 20 minutes to fully mix various raw materials. Put the mixed powder into the BN crucible, the bulk relative density is about 30%, then cover the non-sealed top cover, put it into the corundum tube furnace, vacuumize the high temperature furnace, and then pass the mixed reducing gas That is, in the flowing NH ₃ ambient atmosphere with a purity of 99.999%, the temperature was raised to 1000°C at a heating rate of 5°C/min, and then raised to 1550°C at a heating rate of 4°C/min, kept for 6 hours, and then heated at 4°C /min cooling rate to 800°C, then naturally cool to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the required phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra ( FIG. 8 ). Experiments have proved that by adjusting the ratio of alkaline earth elements Ba and Sr, the emission wavelength can fluctuate in the range of 470nm-475nm, which has a positive effect on the regulation of emission wavelength.

Example 8

According to the chemical formula Ba _0.55 Ca _0.4 Eu _0.15 Si ₃ Al ₃ O ₄ N ₅ , weigh 0.3168g Eu ₂ O ₃ , 1.2186g Al ₂ O ₃ , 1.7536g Si ₃ N ₄ , 0.4968g AlN, 1.0656g BaCO ₃ and 0.4804g SrCO ₃ as The starting powder is put into a silicon nitride mortar and ground for 20 minutes to fully mix various raw materials. Put the mixed powder into the BN crucible, the bulk relative density is about 30%, then cover the non-sealed top cover, put it into the corundum tube furnace, vacuumize the high temperature furnace, and then pass the mixed reducing gas That is, in the flowing NH ₃ ambient atmosphere with a purity of 99.999%, the temperature was raised to 1000°C at a heating rate of 5°C/min, and then to 1500°C at a heating rate of 4°C/min, kept for 6 hours, and then heated at 4°C /min cooling rate to 800°C, then naturally cool to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the required phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra ( FIG. 9 ). Experiments have proved that by adjusting the ratio of alkaline earth elements Ba and Ca, the emission wavelength can fluctuate in the range of 470nm-530nm, and at the same time, the temperature of powder synthesis can be appropriately reduced and the emission wavelength can be adjusted, which has a positive effect on industrial production.

Example 9

According to the chemical formula Ba _0.55 Zn _0.2 Eu _0.15 Si ₃ Al ₃ O ₄ N ₅ , weigh 0.3168g Eu ₂ O ₃ , 1.2186g Al ₂ O ₃ , 1.7536g Si ₃ N ₄ , 0.4968g AlN, 1.0656g BaCO ₃ and 0.1954g ZnO as starting Put the raw powder together into a silicon nitride mortar and grind for 20 minutes to fully mix various raw materials. Put the mixed powder into the BN crucible, the bulk relative density is about 30%, then cover the non-sealed top cover, put it into the corundum tube furnace, vacuumize the high temperature furnace, and then pass the mixed reducing gas That is, in the flowing NH ₃ ambient atmosphere with a purity of 99.999%, the temperature was raised to 1000°C at a heating rate of 5°C/min, and then raised to 1550°C at a heating rate of 4°C/min, kept for 6 hours, and then heated at 4°C /min cooling rate to 800°C, then naturally cool to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the required phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra ( FIG. 10 ). Experiments have proved that by adjusting the ratio of the element Zn in the crystal, the emission wavelength and luminous intensity can fluctuate within a certain range, which can play a role in adjusting the color purity of the phosphor.

Example 10

According to the chemical formula Ba _0.85 Eu _0.15 Si ₃ Al ₂ Ga ₁ O ₄ N ₅ , weigh 0.1584g Eu ₂ O ₃ , 0.3059g _{Al 2} O ₃ , 0.8714g Si ₃ N ₄ , 0.2459g AlN, 1.0064g BaCO ₃ and 0.5623g Ga ₂ O ₃ As the starting powder, put them together into an agate ball mill jar and grind them for 20 hours to fully mix various raw materials. Dry the mixed powder and put it into a BN crucible, with a bulk density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, vacuumize the high temperature furnace, and then pass it into The mixed reducing gas is heated to 1000°C at a heating rate of 5°C/min in a flowing NH ₃ ambient atmosphere with a purity of 99.999%, and then raised to 1500°C at a heating rate of 4°C/min, kept for 4 hours, and then Cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the desired phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra ( FIG. 11 ). Experiments have proved that by adjusting the ratio of elements Al and Ga in the crystal, the peak of the emission wavelength can be moved within 470nm-480nm, and the adjustment in the blue light band can be realized, which plays a positive role in the adjustment of the color purity of the phosphor. On the other hand, the doping of Ga can greatly reduce the synthesis temperature of the powder, and also has a certain effect on reducing the synthesis cost of the powder.

Example 11

Prepare powder according to the chemical formula Ba _0.85 Eu _0.15 Si ₃ Al ₂ InO ₄ N ₅ , weigh 0.1584gEu ₂ O ₃ , 0.3059gAl ₂ O ₃ , 0.8714gSi ₃ N ₄ , 0.2459gAlN, 1.0064gBaCO ₃ and 0.8329gIn ₂ O ₃ As the starting powder, put it into a silicon nitride mortar and grind it for 40 minutes to fully mix various raw materials. Mix all ingredients thoroughly. Dry the mixed powder and put it into a BN crucible, with a bulk density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, vacuumize the high temperature furnace, and then pass it into The mixed reducing gas is heated to 1000°C at a rate of 5°C/min in a flowing NH ₃ ambient atmosphere with a purity of 99.999%, and then raised to 1500°C at a rate of 4°C/min, kept for 6 hours, and then Cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the desired phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra ( FIG. 12 ). Experiments have proved that by adjusting the ratio of elements Al and In in the crystal, the peak of the emission wavelength can be moved within 470-480nm, and the adjustment in the blue light band can be realized, which plays a positive role in the adjustment of the color purity of the phosphor; On the other hand, the incorporation of In can greatly reduce the synthesis temperature of the powder, and also has a certain effect on reducing the synthesis cost of the powder.

Example 12

Composition according to the chemical formula Ba _0.85 Eu _0.15 Si _{3-x Gex} O ₄ N ₅ , take x = 0.5, prepare powder according to the chemical formula Ba _0.85 Eu _0.15 Si _2.5 Ge _0.5 O ₄ N ₅ , weigh 0.1584g Eu ₂ O ₃ , 0.4062g Al ₂ O ₃ , 0.7014g Si ₃ N ₄ , 0.4098g AlN, 1.0064g BaCO ₃ and 0.3139g GeO ₂ are used as starting powders, and they are put into a silicon nitride mortar and ground for 40 minutes to fully mix various raw materials. Mix all ingredients thoroughly. Dry the mixed powder and put it into a BN crucible, with a bulk density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, vacuumize the high temperature furnace, and then pass it into The mixed reducing gas is heated to 1000°C at a rate of 5°C/min in a flowing _N2 ambient atmosphere with a purity of 99.999%, and then raised to 1500°C at a rate of 4°C/min, kept for 6 hours, and then Cool down to 800°C at a cooling rate of 4°C/min, then cool naturally to room temperature, take out the obtained powder, put it in a mortar and grind it into powder to obtain the desired phosphor. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra. The incorporation of Ge can replace the position of Si in the crystal lattice, and at the same time, adjusting the content of Ge within a certain range can change the wavelength of the emission spectrum of the matrix. Experiments have proved that under the excitation of ultraviolet light, the powder has a strong emission in a wide spectral range of 450-500nm.

Example 13

According to the chemical formula Ba _0.85 Eu _0.15 Si _3-x B _x Al ₃ O _4+3/2x N _5-4/3x , take x=0.3, according to the chemical formula Ba _0.85 Eu _0.15 Si _2.6 B _0.4 Al ₃ O _4.45 N _4.6 Powder, weigh 0.1584g Eu ₂ O ₃ , 0.6093g Al ₂ O ₃ , 0.7295g Si ₃ N ₄ , 0.2459g AlN, 1.0064g BaCO ₃ and 0.1113g H ₃ BO ₃ as the starting powder, and put them together into a silicon nitride mortar Thoroughly grind for 40 minutes to fully mix the various raw materials. Mix all ingredients thoroughly. Dry the mixed powder and put it into a BN crucible, with a bulk density of about 30%, then cover it with a non-sealed top cover, put it into a corundum tube furnace, vacuumize the high temperature furnace, and then pass it into Mixed reducing gas means that in a mixed atmosphere of flowing NH ₃ and N ₂ (volume ratio 1:4) with a purity of 99.999%, the temperature is raised to 1000°C at a rate of 5°C/min, and then the temperature is raised at a rate of 4°C/min. Raise the temperature to 1500°C, keep it warm for 6 hours, then cool down to 800°C at a cooling rate of 4°C/min, then cool down to room temperature naturally, take out the obtained powder, put it in a mortar and grind it into powder to obtain the required fluorescence pink. The fluorescence conversion performance of the powder is characterized by measuring its excitation and emission spectra. Experiments demonstrate that the charge imbalance due to the valence mismatch between Si and B can be tuned by the ratio of O and N in the crystal structure itself. The obtained fluorescent powder can be excited by a wide band from vacuum ultraviolet and near ultraviolet to blue light, emits bright blue light with a center wavelength of 472nm, and the excitation and emission intensity in the blue light band is 20% higher than that of commercial BAM blue powder.

The silicon oxynitride phosphor powder provided by the present invention and its preparation method have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (23)

1. A silicon oxynitride fluorescent powder, characterized in that, the general formula is: Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d , wherein- 2<a<2, -2<b<2, -2<c<2, -2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D = 2, e >0, v _C , v _D represent C, the valence state of D; C is selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, The luminescent center of one or more elements in Pb and Fe, D is a mixture of alkaline earth metals other than Ba and one or more elements in Zn. 2. The silicon oxynitride phosphor according to claim 1, characterized in that the general formula is: Ba _1-fg C _f D _g Si ₃ (Al, Ga, In) ₃ O ₄ N ₅ , 0≤f ≤0.30, 0≤g≤0.5; C is one selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, Fe Or the luminescent center of several elements, D is an alkaline earth metal other than Ba and a mixture of one or several elements in metal elements. 3. The silicon oxynitride phosphor powder according to claim 2, characterized in that its basic structure is a monoclinic crystal structure composed of BaSi ₃ Al ₃ O ₄ N ₅ , and its crystal phase uses CuKα as the X-ray source In the XRD diffraction test, there are diffraction peaks in the following three 2θ: 24.3°-26.3°, 30.7°-32.7°, 35.6°-37.6°. 4. The silicon oxynitride phosphor according to any one of claims 1 to 3, characterized in that the Si may be partially replaced by Ge or B. 5. The silicon oxynitride phosphor according to any one of claims 1 to 3, wherein the C is a luminescence center containing at least one element among Ce, Sm, Eu or Yb. 6. The silicon oxynitride phosphor powder according to any one of claims 1 to 3, characterized in that, in the fluorescence spectrum, the maximum emission wavelength is 460nm-500nm, and in the excitation spectrum, the maximum excitation wavelength is 240nm-420nm, In vacuum ultraviolet excitation, the maximum excitation wavelength is 140nm-155nm. 7. The silicon oxynitride phosphor according to any one of claims 1 to 3, characterized in that the maximum emission wavelength in the fluorescence spectrum is 400nm-440nm, and the maximum excitation wavelength in the excitation spectrum is 250nm-370nm. 8. The silicon oxynitride phosphor according to any one of claims 1 to 3, characterized in that the maximum emission wavelength in the fluorescence spectrum is 300nm-550nm, and the maximum excitation wavelength in the excitation spectrum is 650nm-740nm. 9. A method for preparing a silicon oxynitride fluorescent powder, comprising the following steps: 1) According to the chemical expression Ba _e C _f D _g Si _3+a (Al, Ga, In) _3+b O _4+c N _5+d , calculate the amount of each raw material according to the ratio of each element, where -2<a <2, -2<b<2, -2<c<2, -2<d<2, 0≤f≤0.30, 0≤g≤0.5, 2e+fv _C +gv _D =2, e>0, v _C , v _D represents C, the valence state of D; C is selected from Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Mn, Cr, Bi, Pb, Fe The luminescent center of one or more elements in D, D is a mixture of alkaline earth metals other than Ba and one or more elements in Zn; Each raw material is: one or several barium-containing compounds in barium oxide or barium carbonate or barium oxalate that can be converted into barium oxide, including Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, One or several elements of Tm, Yb, Mn, Cr, Bi, Pb, Fe, oxides, nitrides or compounds that can be converted into oxides or nitrides, containing alkaline earth metals other than Ba and one of Zn Or several simple substances, oxides, nitrides or compounds that can be converted into oxides or nitrides, Si-containing oxides, nitrides or compounds that can be converted into oxides or nitrides; 2) Mix the above-mentioned various raw materials, and heat the mixture to 1400°C-1600°C in a reducing atmosphere for roasting, keep it warm for 2h-40h, and naturally cool to room temperature; 3) Pulverize the powder obtained after firing to a particle size of 10 μm or less. 10. The preparation method according to claim 9, characterized in that, the raw materials in 2) further include oxides, nitrides or compounds that can be converted into oxides or nitrides containing Ge or B. 11. The preparation method according to claim 9 or 10, characterized in that, after mixing the above-mentioned various raw materials in 2), a co-solvent H ₃ BO ₃ or BaF ₂ is also added. 12. The preparation method according to claim 9 or 10, characterized in that, the mixing device used for mixing the above-mentioned various raw materials in 2) is a V-type mixer, a shaking mixer, a ball mill, or a vibrating ball mill. 13. The preparation method according to claim 9 or 10, characterized in that, after the above-mentioned various raw materials are mixed in the 2), the mixture is filled with boron nitride, silicon nitride, tungsten, molybdenum or aluminum oxide In a crucible with low reactivity. 14. The preparation method according to claim 9 or 10, characterized in that, after mixing the above-mentioned various raw materials in 2), the bulk relative density is controlled at 20%-40%. 15. The preparation method according to claim 9 or 10, characterized in that, the reducing atmosphere in 2) is one or more mixed atmospheres of nitrogen, hydrogen or ammonia. 16. The preparation method according to claim 15, characterized in that the pressure of the reducing atmosphere is above 1 atm. 17. The preparation method according to claim 9 or 10, characterized in that the heating rate of the mixture in 2) is 1°C/min-10°C/min. 18. The preparation method according to claim 9 or 10, characterized in that, the furnace used for roasting in the 2) is a continuous furnace or a batch furnace of a metal resistance heating type, a graphite resistance heating type or a silicon molybdenum rod resistance heating type . 19. A phosphor composition, characterized in that it comprises the silicon oxynitride phosphor according to any one of claims 1 to 8, the silicon oxynitride phosphor accounting for the weight of the phosphor composition The percentage is 25% or more. 20. A lighting device, characterized in that it comprises a light-emitting light source and the silicon oxynitride phosphor according to any one of claims 1 to 8, and the lighting device is a white LED lamp or a trichromatic fluorescent lamp. 21. The lighting device according to claim 20, characterized in that, the light emitting source is an LED with a light emitting wavelength of 320nm-470nm. 22. An image display device, characterized in that it comprises an excitation source and the silicon oxynitride phosphor powder according to any one of claims 1 to 8, the image display device is a fluorescent display tube, a field emission display, One of plasma displays, cathode ray tubes, and high-definition televisions. 23. The image display device according to claim 22, wherein the excitation source is one of electron rays, electric field, vacuum ultraviolet rays or ultraviolet rays.

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